The Jolla phone, which I like because it's an open-source and
ad-free platform which will not send all my data to Google, also has a user-replacable battery. Even if
spares are rares, batteries made for HTC Desire 210 are a perfect fit and same technology. Having now two
batteries, it also allow me to swap for a charged one when the one i'm using is flat. It's much more handy
than having a large usb charger connected to the phone when i'm at a event or something. The problem is,
swapping the batteries for charging them all with the phone is much less convenient. Especially when you can
do only one charge when you are sleeping.. if you have time to sleep. Thus, the necessity of an external
battery charger. The battery contacts and charger board are from eBay. If you plan to do something like this,
be sure the charger board have compatible electrical properties to the battery you're using. The
milling machine only has stepper motors, and is has been equipped with step/dir controllers. These
signals (step-clock and direction) are directly generated with a computer running LinuxCNC. That distribution is using a RTAI real-time patched
kernel, for minimal step-clock jitter.

The goal : charging a Jolla battery outside of the Jolla phone

Making the basic shapes with Cambam Free

After the configuration of the tools, depths, and other properties, time to generate the tool
moves

We can have already in 3D the machine's moves. Now we're exporting a G-Code file...

Bonus: Before i've found the battery contacts, i tought about
using these pins usually found on "fakir plank", part of the rigging for automated
testing of finished printed circuits boards... it would not fit!